The nocturnal beetle known for producing light through bioluminescence is the firefly. Fireflies are beetles in the family Lampyridae, and their flashes are chemical signals rather than reflected moonlight or electrical sparks.
The light is produced in specialized organs, usually near the end of the abdomen. A reaction involving luciferin, the enzyme luciferase, oxygen, and cellular energy releases light with very little heat, which is why it is often called “cold light.” Different species use distinctive flash patterns to attract mates, identify their own kind, or warn predators that they taste unpleasant.
“Firefly,” “lightning bug,” and “glowworm” can describe related lampyrid beetles, but they are not always interchangeable. In many species, larvae glow and wingless females may also be called glowworms. Fireflies are not the same as click beetles, whose name refers to a clicking escape mechanism, nor are they scarab beetles. Their flashing is most visible at dusk or night in warm, humid habitats.